Mr. Papin (the inventor) having fixed all things right, and included about a pint of water, with two ounces of marrow-bone, he placed the vessel horizontally between the bars of the grate, about half-way into the fire. In three minutes he found it raised to a great heat, and perceiving the heat in a very short time become more raging, stepped to a side-table for an iron to take the digester out of the fire, when it suddenly burst with the explosion of a musket. It was heard at a considerable distance, and actually shook the house. The bottom of the vessel that was in the fire gave way; the blast of the expanded water blew all the coals out of the fire into the room, the remainder of the vessel flew across the room, and, hitting the leaf of an oak table, an inch thick, broke it all in pieces, and rebounded half the length of the room back again. He could not perceive the least sign of water, though he looked carefully for it; the fire was quite extinguished, and every coal black in an instant.
The following accident was attended with more fatal consequences.
A steam-engine was repairing at Chelsea, and, as the workmen were endeavouring to discover the defect, the boiler suddenly exploded, and a cloud of steam rushing out at the fracture, struck one of the men who was near it, like a blast of lightning, and killed him in a moment; when his companions endeavoured to take off his clothes, the flesh came off with them from the bones.
Account of the Wonderful Effects of two immense Burning-Glasses.
Mr. de Tschirnhausen constructed a burning-glass, between three and four feet in diameter, and whose focus was rendered more powerful by a second one. This glass melted tiles, slates, pumice-stone, &c., in a moment; pitch, and all resins, were melted even under water; the ashes of vegetables, wood, and other matters, were converted into glass; indeed, it either melted, calcined, or dissipated into smoke, every thing applied to its focus.
Mr. Parker, of Fleet-street, made a burning-glass, three feet in diameter; it was formed of flint glass, and when on its frame, exposed a surface of 2 feet 8½ inches to the solar rays. It had a small glass fitted to it, to converge the rays, and heighten the effect. The experiments made by it were more powerful and accurate than those performed by any other glass. The following is a brief epitome of its astonishing power.
| Substances melted, with their weight; and the Time in Seconds, which they took in melting. | Weight in Grains. | Time in Seconds. |
|---|---|---|
| Pure gold | 20 | 4 |
| Pure silver | 20 | 3 |
| Pure copper | 33 | 20 |
| Pure platina | 10 | 3 |
| Nickel | 16 | 3 |
| A cube of bar-iron | 10 | 12 |
| A cube of cast-iron | 10 | 3 |
| A cube of steel | 10 | 12 |
| Scoria of wrought-iron | 12 | 2 |
| Kearsh | 10 | 3 |
| Cauk, or terra ponderosa | 10 | 7 |
| A topaz, or chrysolite | 3 | 45 |
| An oriental emerald | 2 | 25 |
| Crystal pebble | 7 | 6 |
| White agate | 10 | 30 |
| Oriental flint | 10 | 30 |
| Rough cornelian | 10 | 75 |
| Jasper | 10 | 25 |
| Onyx | 10 | 20 |
| Garnet | 10 | 17 |
| White rhomboidal spar | 10 | 60 |
| Zeolites | 10 | 23 |
| Rotten-stone | 10 | 80 |
| Common slate | 10 | 2 |
| Asbestos | 10 | 10 |
| Common lime-stone | 10 | 55 |
| Pumice-stone | 10 | 24 |
| Lava | 10 | 7 |
| Volcanic clay | 10 | 60 |
| Cornish moor-stone | 10 | 60 |
Fulminating Powder.
This powder is made by rubbing together, in a hot marble mortar, with a wooden pestle, three parts, by weight, of nitre, two of mild vegetable alkali, and one of flowers of sulphur, till the whole is accurately mixed. If a drachm of this powder be exposed to a gentle heat, in an iron ladle, till it melts, it will explode with a noise as loud as the report of a cannon.